Protease-cellulase compound enzyme preparation for full-component utilization of spent grains

Abstract

The invention relates to the technical field of high-value utilization of beer brewing byproducts, and discloses a spent grain all-component utilization protease-cellulase compound enzyme preparation which is prepared from the following raw materials in percentage by mass: 50-60% of protease, 10-30% of cellulase, 10-30% of hemicellulase and 10-30% of sodium citrate. 25%-35% of cellulase; 10%-20% of hemicellulase; the prepared compound enzyme preparation is applied to a spent grain conversion process of three-stage synergetic enzymolysis, by designing a staged enzymolysis process of acid first and alkali second, all enzyme systems are activated in sequence under the optimal condition, cellulase and hemicellulase break fiber barriers preferentially in the acid stage, and the enzyme systems are activated in sequence under the optimal condition. The method has the advantages that the method is simple and convenient to operate, the accessibility of subsequent protease to substrates is improved, the protein extraction rate and the fiber conversion rate are increased, the spent grain protein and fiber synchronous efficient conversion and almost all-component resource utilization are realized, and the problems of incomplete resource conversion and easy generation of secondary solid waste in a traditional treatment mode are thoroughly solved.

Description

Technical Field

[0001] This invention relates to the field of high-value utilization of beer brewing by-products, specifically to a protease-cellulase complex enzyme preparation for the full utilization of malt residue. Background Technology

[0002] Wheat lees are a major byproduct of beer production, with a huge annual output, and are rich in nutrients such as protein, cellulose, and hemicellulose. Currently, the utilization of wheat lees is relatively limited or low-value, with most being used as animal feed or directly discarded, resulting in resource waste and environmental pollution.

[0003] In existing technologies, although some studies have attempted to use single enzymes or simple enzyme mixtures to treat wheat bran to extract proteins or degrade fibers, these methods generally suffer from problems such as low enzymatic hydrolysis efficiency, weak synergistic effects, and low yields of the target products. For example, when using proteases alone, the dense cell walls composed of cellulose and hemicellulose in wheat bran make it difficult for proteases to effectively contact the internal proteins, resulting in limited protein extraction rates. While cellulase treatment alone can degrade some fibers, it cannot achieve high-value conversion of proteins. Furthermore, existing compound enzyme treatments often employ simple mixing or one-step enzymatic hydrolysis, failing to fully consider the differences in the optimal operating conditions of each enzyme, resulting in insufficient enzyme activity and inadequate process stability and reproducibility.

[0004] Therefore, developing a complex enzyme preparation and supporting process that can work synergistically and adapt to different conditions to achieve efficient and high-value utilization of all components of wheat lees has become a technical challenge that the industry urgently needs to solve. Summary of the Invention

[0005] (a) Technical problems to be solved

[0006] To address the shortcomings of existing technologies, this invention provides a protease-cellulase composite enzyme preparation for the complete utilization of wheat lees. It has the advantages of stable enzyme activity, high efficiency of multi-enzyme synergy, complete utilization of all components, and no solid waste discharge. It solves the problems of low degradation efficiency of single enzyme preparations, unstable activity of composite enzymes, difficulty in breaking down the cell wall structure barrier of wheat lees, inability to synchronize protein extraction and fiber degradation, high solid waste residue rate, and low comprehensive utilization rate of raw materials.

[0007] (II) Technical Solution

[0008] To achieve the above objectives, the present invention provides the following technical solution: a protease-cellulase complex enzyme preparation for the whole components of wheat lees, wherein the complex enzyme preparation is composed of protease, cellulase, hemicellulase and sodium citrate, and the raw material mass percentages are: protease 50%-60%; cellulase 25%-35%; hemicellulase 10%-20%; sodium citrate 0.2%-0.5%.

[0009] Preferably, the preparation process of the protease is as follows:

[0010] S1.1, Strain selection and fermentation: Aspergillus oryzae strains were selected and deep liquid fermentation was carried out in an optimized culture medium at 32-36℃ and pH 6.5-7.5.

[0011] S1.2 Enzyme extraction: After fermentation, the fermentation broth is filtered through a 0.22-0.45μm plate and frame filter until the cell removal rate is ≥99% to obtain enzyme-containing fermentation broth;

[0012] S1.3, Crude separation: The mixture is then concentrated using a 10-30 kDa ultrafiltration membrane, followed by fractional precipitation with 30-50% saturated ammonium sulfate at 0-4℃ and pH 4.5-5.5 to obtain the crude enzyme preparation.

[0013] S1.4 Enzyme formulation: Crude enzyme solution, glycerol and maltodextrin are mixed in a mass ratio of 1:0.2:0.8 and spray-dried to prepare standardized protease powder, so that the final enzyme activity is stable at 80,000 to 150,000 U / g, and stored at a low temperature of 1-4℃ for later use.

[0014] Preferably, the cellulase is selected from one of Trichoderma reesei cellulase, Aspergillus niger cellulase, Trichoderma longibranchii cellulase, and Penicillium obliquus cellulase; the hemicellulase is selected from one of Trichoderma hemicellulase, Aspergillus hemicellulase, and Bacillus subtilis hemicellulase.

[0015] Preferably, the whole component of wheat lees is prepared using a protease-cellulase complex enzyme preparation, comprising the following preparation steps:

[0016] Step 1: Raw material preparation: Weigh out the protease, cellulase, hemicellulase and sodium citrate according to the proportions;

[0017] Step 2: Pre-prepared enzyme powder: Cellulase and hemicellulase are pretreated under set conditions to prepare pre-prepared enzyme powder.

[0018] Step 3, Dry premixing: Add protease powder to the pre-prepared enzyme powder and perform preliminary physical mixing under dry and low-temperature conditions;

[0019] Step 4, Final Mixing and Homogenization: Add sodium citrate to the premixed enzyme powder and perform final homogenization to obtain the compound enzyme preparation.

[0020] Preferably, in step two, the pre-prepared enzyme powder is prepared by mixing cellulase with 10%-15% of its mass of maltodextrin carrier and 3%-5% of glycerol protectant in a buffer system with pH 4.5-5.5, and then spray-drying it at an inlet air temperature of 170-175℃ and an outlet air temperature of 75-80℃ to prepare pre-prepared enzyme powder, which is then stored at a low temperature of 1-4℃ for later use.

[0021] Preferably, in step two, the pre-prepared enzyme powder is prepared by mixing hemicellulase with 8%-12% of its mass of maltodextrin carrier and 2%-4% of sorbitol protectant in a buffer system with pH 4.5-5.0, and then spray-drying it at an inlet air temperature of 160-170℃ and an outlet air temperature of 70-75℃ to prepare pre-prepared enzyme powder, which is then stored at a low temperature of 1-4℃ for later use.

[0022] Preferably, the mixing conditions in step three are set as follows: the mixing equipment speed is 8-12 rpm, and an intermittent mixing program is adopted, which first mixes at a low speed of 3-5 rpm for 5-10 minutes to disperse the material, and then mixes at a medium speed of 15-20 rpm for 10-30 minutes.

[0023] Preferably, the homogenization conditions in step four are set as follows: the mixing equipment speed is 10-15 rpm, a continuous mixing mode is adopted, and samples are taken at the beginning, middle and end of the mixing process. The coefficient of variation of the mixing uniformity is ≤3% and the deviation of the protease / cellulase activity ratio is ≤5% by rapid detection through near-infrared spectroscopy.

[0024] Preferably, the compound enzyme preparation is applied to all components of wheat lees for staged enzymatic hydrolysis and simultaneous saccharification, and the specific steps are as follows:

[0025] T1. Pretreatment of wheat lees: Crush wet wheat lees with a moisture content of 75-80% to 40-60 mesh, add water to make a slurry at a solid-liquid ratio of 1:5-1:8, sterilize at 80-85℃ for 13-15 minutes, and cool to 50-55℃ for later use.

[0026] T2. Staged enzymatic hydrolysis: Add compound enzyme preparation to the pretreated wheat lees slurry in three stages;

[0027] T3. Product separation: After enzymatic hydrolysis, the supernatant and residue are separated by centrifugation. The supernatant is concentrated by ultrafiltration to a solid content of 18-20%, and the residue is dried and used as a feed additive to achieve full utilization of the components.

[0028] Preferably, the conditions for the T2 enzymatic hydrolysis are as follows: in the first stage, 0.095-0.105% of mesophilic α-amylase is added, and the hydrolysis is carried out at 50-55℃ and pH 6.0-6.5 for 1-1.5 hours; in the second stage, 0.5-0.8% of a compound enzyme preparation is added according to the dry weight of the wheat lees, and the hydrolysis is carried out at 45-50℃ and pH 6.5-7.0 for 3-4 hours; in the third stage, 0.05% of an endopeptidase is added, and the hydrolysis is carried out at 40-45℃ and pH 5.5-6.0 for 1-1.5 hours.

[0029] Compared with the prior art, the present invention provides a protease-cellulase complex enzyme preparation for the complete utilization of wheat lees, which has the following beneficial effects:

[0030] 1. This invention achieves the beneficial effect of sequential activation and synergistic effect of each enzyme system under optimal conditions by using a precise ratio (4:2:1:0.3) of protease, cellulase, hemicellulase and sodium citrate and a staged enzymatic hydrolysis process of acid-first and alkali-second. In particular, cellulase and hemicellulase preferentially break down the fiber barrier in the acidic stage, which can effectively improve the accessibility of the substrate to the subsequent protease, thereby increasing the protein extraction rate and fiber conversion rate.

[0031] 2. This invention uses pre-prepared enzyme powder standardization and dry gradient mixing process to ensure high stability, high uniformity and reproducibility of compound enzyme preparations. By protecting each enzyme with a carrier and spray drying pretreatment, and combining a low-speed dispersion and medium-speed homogenization mixing program with near-infrared spectroscopy online quality control, the uniformity of the preparation mixing is increased, thereby overcoming the problems of easy stratification and unstable activity caused by simple physical mixing in traditional processes.

[0032] 3. This invention applies a compound enzyme preparation to a three-stage synergistic enzymatic hydrolysis process for wheat lees conversion, thereby achieving simultaneous and efficient conversion of wheat lees protein and fiber and near-complete resource utilization. Ultimately, the wheat lees residue rate is less than 5%, and the product is rich in soluble peptides, amino acids, and functional oligosaccharides. This not only completely solves the problems of incomplete resource conversion and easy generation of secondary solid waste in traditional treatment methods, but also meets the requirements of circular economy and green manufacturing. Attached Figure Description

[0033] Figure 1 This is a flowchart illustrating the application of the compound enzyme preparation of the present invention. Detailed Implementation

[0034] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0035] Please see Figure 1 The whole component of wheat lees utilizes a protease-cellulase complex enzyme preparation. The complex enzyme preparation is composed of protease, cellulase, hemicellulase and sodium citrate. The raw material mass percentage is as follows: protease 50%-60%; cellulase 25%-35%; hemicellulase 10%-20%; sodium citrate 0.2%-0.5%.

[0036] Specifically, the raw materials serve the following purposes:

[0037] Table 1

[0038] Components Ratio (mass ratio) Content range (as a percentage of total enzyme preparation) Main functions protease 4 50%～60% Hydrolyzing residual proteins in wheat lees releases soluble peptides and amino acids, improving protein utilization. Cellulase 2 25%～35% It degrades cellulose into fermentable sugars, breaks down the fiber structure, and promotes the release of proteins and other components. hemicellulase 1 10%～20% It breaks down hemicellulose and works with cellulase to break down cell wall structures, improving the accessibility of raw materials. Sodium citrate 0.3% (added externally) 0.2%～0.5% As a pH buffer and metal ion chelator, it stabilizes the enzyme activity environment and improves enzymatic hydrolysis efficiency.

[0039] Specifically, the preparation process of protease:

[0040] S1.1, Strain selection and fermentation: Aspergillus oryzae strains were selected and deep liquid fermentation was carried out in an optimized culture medium at 32-36℃ and pH 6.5-7.5.

[0041] S1.2 Enzyme extraction: After fermentation, the fermentation broth is filtered through a 0.22-0.45μm plate and frame filter until the cell removal rate is ≥99% to obtain enzyme-containing fermentation broth;

[0042] S1.3, Crude separation: The mixture is then concentrated using a 10-30 kDa ultrafiltration membrane, followed by fractional precipitation with 30-50% saturated ammonium sulfate at 0-4℃ and pH 4.5-5.5 to obtain the crude enzyme preparation.

[0043] S1.4 Enzyme formulation: Crude enzyme solution, glycerol and maltodextrin are mixed in a mass ratio of 1:0.2:0.8 and spray-dried to prepare standardized protease powder, so that the final enzyme activity is stable at 80,000 to 150,000 U / g, and stored at a low temperature of 1-4℃ for later use.

[0044] The advantages are: the combination of fermentation, membrane separation and fractionation precipitation achieves efficient extraction and purification of proteases, while the addition of glycerol and maltodextrin in the spray drying process can effectively protect the enzyme activity, thereby improving its stability and flowability.

[0045] Specifically, the cellulase is selected from one of Trichoderma reesei cellulase, Aspergillus niger cellulase, Trichoderma longibranchii cellulase, and Penicillium obliquus cellulase; the hemicellulase is selected from one of Trichoderma hemicellulase, Aspergillus hemicellulase, and Bacillus subtilis hemicellulase.

[0046] The whole-component bran lees preparation utilizes a protease-cellulase complex enzyme preparation, which includes the following preparation steps:

[0047] Step 1: Raw material preparation: Weigh out the protease, cellulase, hemicellulase and sodium citrate according to the proportions;

[0048] Step 2, Pre-prepared enzyme powder: Cellulase and hemicellulase are pretreated separately under set conditions to prepare pre-prepared enzyme powder (protease is not pretreated and is kept in its original powder state to avoid premature activation and degradation).

[0049] Step 3, Dry premixing: Add protease powder to the pre-prepared enzyme powder and perform preliminary physical mixing under dry and low temperature (≤25℃) conditions;

[0050] Step 4, Final Mixing and Homogenization: Add sodium citrate to the premixed enzyme powder and perform final homogenization to obtain a homogeneous compound enzyme preparation.

[0051] Specifically, in step two, the pre-prepared enzyme powder is prepared by mixing cellulase with 10%-15% maltodextrin carrier and 3%-5% glycerol protectant in a buffer system with pH 4.5-5.5, and then spray-drying it at an inlet air temperature of 170-175℃ and an outlet air temperature of 75-80℃ to prepare a pre-prepared enzyme powder with good flowability. It is then stored at a low temperature of 1-4℃ for later use.

[0052] Specifically, in step two, the pre-prepared enzyme powder is prepared by mixing hemicellulase with 8%-12% of its mass of maltodextrin carrier and 2%-4% of sorbitol protectant in a buffer system with pH 4.5-5.0, and then spray-drying it at an inlet air temperature of 160-170℃ and an outlet air temperature of 70-75℃ to prepare a pre-prepared enzyme powder with good flowability, which is then stored at a low temperature of 1-4℃ for later use.

[0053] The advantages are: by adding carriers and protectants, the activity retention rate of single enzyme preparations can be improved during storage, while the differences in physical properties between different batches of liquid enzyme raw materials can be eliminated, laying a solid foundation for the uniform mixing of subsequent dry compounding.

[0054] Specifically, the mixing conditions in step three are set as follows: the mixing equipment speed is 8-12 rpm, and an intermittent mixing process is adopted, first mixing at a low speed of 3-5 rpm for 5-10 minutes to disperse the material, and then mixing at a medium speed of 15-20 rpm for 10-30 minutes, to ensure that the material does not separate or clump.

[0055] The advantages are: the low-speed stage (3-5 rpm) achieves macroscopic dispersion of materials with different densities and particle sizes, preventing agglomeration and dust; the medium-speed stage (15-20 rpm) promotes microscopic convection and shear mixing of materials. This process ensures the uniformity of mixing while effectively avoiding enzyme protein denaturation caused by mechanical heating, thereby ensuring the activity of each enzyme component.

[0056] Specifically, the homogenization conditions in step four are set as follows: the mixing equipment speed is 10-15 rpm, a continuous mixing mode is adopted, and samples are taken at the beginning, middle and end of the mixing process. The coefficient of variation (CV) of the mixing uniformity is ≤3% and the deviation of the protease / cellulase activity ratio is ≤5% by near-infrared spectroscopy (NIR).

[0057] The advantage is that by introducing near-infrared spectroscopy (NIR) online detection as a process analysis technique (PAT), real-time and non-destructive monitoring of mixing uniformity can be achieved.

[0058] Specifically, the compound enzyme preparation is applied to all components of wheat lees for staged enzymatic hydrolysis and simultaneous saccharification. The specific steps are as follows:

[0059] T1. Pretreatment of wheat lees: Crush wet wheat lees with a moisture content of 75-80% to 40-60 mesh, add water to make a slurry at a solid-liquid ratio of 1:5-1:8, sterilize at 80-85℃ for 13-15 minutes, and cool to 50-55℃ for later use.

[0060] T2. Staged enzymatic hydrolysis: Add compound enzyme preparation to the pretreated wheat lees slurry in three stages;

[0061] T3. Product separation: After enzymatic hydrolysis, centrifugation is used to separate the supernatant (rich in peptides and reducing sugars) and the residue (fiber degradation products). The supernatant is concentrated by ultrafiltration to a solid content of 18-20%, and the residue is dried and used as a feed additive to achieve full utilization of the components.

[0062] Specifically, the conditions for T2 enzymatic hydrolysis are as follows: In the first stage, add 0.095-0.105% (w / w) of mesophilic α-amylase and hydrolyze at 50-55℃ and pH 6.0-6.5 for 1-1.5 hours; in the second stage, add 0.5-0.8% of a compound enzyme preparation based on the dry weight of the wheat lees and hydrolyze at 45-50℃ and pH 6.5-7.0 for 3-4 hours; in the third stage, add 0.05% of an endopeptidase and hydrolyze at 40-45℃ and pH 5.5-6.0 for 1-1.5 hours.

[0063] The advantages are: by connecting the temperature (40-55℃) and pH (5.5-7.0) gradients in each stage, the optimal conditions of the compound enzyme and coenzyme are precisely matched, thereby reducing the energy consumption of enzymatic hydrolysis.

[0064] Example 1

[0065] Weigh out 55% of protease (from Aspergillus oryzae, enzyme activity 100,000 U / g), 30% of Trichoderma reesei cellulase (FPA 12,000 U / g), 14.7% of Aspergillus niger hemicellulase (xylanase activity 120,000 U / g), and 0.3% of sodium citrate according to the formula. Strictly follow steps two to four of the preparation method, and mix and homogenize at 20°C and 45% humidity to obtain compound enzyme preparation A.

[0066] Comparative Example 1 (Verifying the synergistic effect of the complex enzyme)

[0067] Using only the single protease (55%) with the same enzymatic activity as in Example 1, and filling the remaining 45% with maltodextrin, without adding cellulase or hemicellulase, a single protease preparation B was prepared in the same manner.

[0068] Example 2

[0069] Weigh out 58% protease (enzyme activity 120,000 U / g), 28% Penicillium arvense cellulase (FPA 15,000 U / g), 13.7% Bacillus subtilis hemicellulase (xylanase activity 150,000 U / g), and 0.3% sodium citrate according to the formula. Prepare the compound enzyme preparation C under the same conditions as in Example 1.

[0070] Comparative Example 2 (verifying the universality of the synergistic effect of the complex enzyme)

[0071] Using only the single protease (58%) with the same enzymatic activity as in Example 2, and filling the remaining 41.7% with maltodextrin, without adding cellulase or hemicellulase, a single protease preparation D was prepared in the same manner.

[0072] The key conversion data of the enzyme preparations prepared in the examples and comparative examples after being applied to the same batch of wheat lees (pretreated in step T1) for enzymatic hydrolysis in stage T2 (only stages two and three were performed, α-amylase treatment was omitted) are recorded in Table 2 below:

[0073] Table 2

[0074] Group Enzyme preparation composition description Protein extraction rate (%) Fiber conversion rate (%) Reducing sugar yield (g / 100g wheat lees) Peptide yield (percentage of extracted protein) Final residue rate (%) Example 1 Compound enzyme preparation A (containing cellulase) 92.5 88.2 32.1 65.8 4.8 Comparative Example 1 Single protease formulation B (without cellulase) 71.3 15.8 5.2 58.4 28.5 Example 2 Compound enzyme preparation C (containing cellulase) 94.1 90.5 34.7 67.2 3.9 Comparative Example 2 Single protease formulation D (without cellulase) 73.6 16.5 5.8 59.1 26.9

[0075] Table 2 shows that the fiber conversion rate of the compound enzyme preparation A / C was 5.4-5.5 times that of the control group, and the reducing sugar yield was 6.2-6.0 times higher. This demonstrates that cellulase and hemicellulase not only efficiently degrade fiber themselves, but also improve protease accessibility by about 30% by disrupting the cell wall structure (protein extraction rate 92.5% vs 71.3%). Therefore, the compound enzyme preparations containing cellulase and hemicellulase in Examples 1 / A or 2 / C have better protein extraction rates, fiber conversion rates, and reducing sugar yields than the corresponding single enzyme preparations containing only protease (Comparative Example 1 / B or Comparative Example 2 / D). This verifies that the compound enzyme preparation of the present invention, through the gradient synergistic effect of protease and fiber-degrading enzyme, can effectively break through the cell wall structure barrier of wheat lees, while simultaneously achieving the simultaneous degradation of protein and cellulose, reducing the residue rate, and improving the comprehensive utilization rate of raw materials. Ultimately, it enables all components of wheat lees to achieve the ESG goal of efficient utilization and zero solid waste discharge.

[0076] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A whole-component protease-cellulase complex enzyme preparation from wheat lees, characterized in that, The compound enzyme preparation is composed of protease, cellulase, hemicellulase and sodium citrate, with the following percentages by mass: protease 50%–60%; cellulase 25%–35%; hemicellulase 10%–20%; sodium citrate 0.2%–0.5%.

2. The wheat lees whole-component protease-cellulase complex enzyme preparation according to claim 1, characterized in that: The preparation process of the protease: S1.1, Strain selection and fermentation: Aspergillus oryzae strains were selected and deep liquid fermentation was carried out in an optimized culture medium at 32-36℃ and pH 6.5-7.

5. S1.2 Enzyme extraction: After fermentation, the fermentation broth is filtered through a 0.22-0.45μm plate and frame filter until the cell removal rate is ≥99% to obtain enzyme-containing fermentation broth; S1.3, Crude separation: The mixture is then concentrated using a 10-30 kDa ultrafiltration membrane, followed by fractional precipitation with 30-50% saturated ammonium sulfate at 0-4℃ and pH 4.5-5.5 to obtain the crude enzyme preparation. S1.4 Enzyme formulation: Crude enzyme solution, glycerol and maltodextrin are mixed in a mass ratio of 1:0.2:0.8 and spray-dried to prepare standardized protease powder, so that the final enzyme activity is stable at 80,000 to 150,000 U / g, and stored at a low temperature of 1-4℃ for later use.

3. The wheat lees whole-component protease-cellulase complex enzyme preparation according to claim 1, characterized in that: The cellulase is selected from one of Trichoderma reesei cellulase, Aspergillus niger cellulase, Trichoderma longibranchii cellulase, and Penicillium obliquus cellulase; the hemicellulase is selected from one of Trichoderma hemicellulase, Aspergillus hemicellulase, and Bacillus subtilis hemicellulase.

4. The wheat lees whole-component protease-cellulase complex enzyme preparation according to claim 1, characterized in that, The preparation steps include the following: Step 1: Raw material preparation: Weigh out the protease, cellulase, hemicellulase and sodium citrate according to the proportions; Step 2: Pre-prepared enzyme powder: Cellulase and hemicellulase are pretreated under set conditions to prepare pre-prepared enzyme powder. Step 3, Dry premixing: Add protease powder to the pre-prepared enzyme powder and perform preliminary physical mixing under dry and low-temperature conditions; Step 4, Final Mixing and Homogenization: Add sodium citrate to the premixed enzyme powder and perform final homogenization to obtain the compound enzyme preparation.

5. The wheat lees whole-component protease-cellulase complex enzyme preparation according to claim 4, characterized in that: In step two, the pre-prepared enzyme powder is prepared by mixing cellulase with 10%-15% maltodextrin carrier and 3%-5% glycerol protectant in a buffer system with pH 4.5-5.5, and then spray-drying it at an inlet air temperature of 170-175℃ and an outlet air temperature of 75-80℃ to prepare pre-prepared enzyme powder, which is then stored at a low temperature of 1-4℃ for later use.

6. The wheat lees whole-component utilization protease-cellulase complex enzyme preparation according to claim 4, characterized in that: In step two, the pre-prepared enzyme powder is prepared by mixing hemicellulase with 8%-12% of its mass of maltodextrin carrier and 2%-4% of sorbitol protectant in a buffer system with pH 4.5-5.0, and then spray-drying it at an inlet air temperature of 160-170℃ and an outlet air temperature of 70-75℃ to prepare pre-prepared enzyme powder, which is then stored at a low temperature of 1-4℃ for later use.

7. The wheat lees whole-component protease-cellulase complex enzyme preparation according to claim 4, characterized in that: In step three, the mixing conditions are set as follows: the mixing equipment speed is 8-12 rpm, and an intermittent mixing program is adopted, which first mixes at a low speed of 3-5 rpm for 5-10 minutes to disperse the material, and then mixes at a medium speed of 15-20 rpm for 10-30 minutes.

8. The wheat lees whole-component protease-cellulase complex enzyme preparation according to claim 4, characterized in that: In step four, the homogenization conditions are set as follows: the mixing equipment speed is 10-15 rpm, a continuous mixing mode is adopted, and samples are taken at the beginning, middle and end of the mixing process. The coefficient of variation of the mixing uniformity is ≤3% and the deviation of the protease / cellulase activity ratio is ≤5% by rapid detection through near-infrared spectroscopy.

9. The wheat lees whole-component protease-cellulase complex enzyme preparation according to claim 1, characterized in that: The compound enzyme preparation is applied to all components of wheat lees for staged enzymatic hydrolysis and simultaneous saccharification. The specific steps are as follows: T1. Pretreatment of wheat lees: Crush wet wheat lees with a moisture content of 75-80% to 40-60 mesh, add water to make a slurry at a solid-liquid ratio of 1:5-1:8, sterilize at 80-85℃ for 13-15 minutes, and cool to 50-55℃ for later use. T2. Staged enzymatic hydrolysis: Add compound enzyme preparation to the pretreated wheat lees slurry in three stages; T3. Product separation: After enzymatic hydrolysis, the supernatant and residue are separated by centrifugation. The supernatant is concentrated by ultrafiltration to a solid content of 18-20%, and the residue is dried and used as a feed additive to achieve full utilization of the components.

10. The wheat lees whole-component protease-cellulase complex enzyme preparation according to claim 1, characterized in that: The conditions for T2 enzymatic hydrolysis are as follows: In the first stage, 0.095-0.105% of mesophilic α-amylase is added, and enzymatic hydrolysis is carried out at 50-55℃ and pH 6.0-6.5 for 1-1.5 hours; in the second stage, 0.5-0.8% of a compound enzyme preparation is added according to the dry weight of the wheat lees, and enzymatic hydrolysis is carried out at 45-50℃ and pH 6.5-7.0 for 3-4 hours; in the third stage, 0.05% of an endopeptidase is added, and enzymatic hydrolysis is carried out at 40-45℃ and pH 5.5-6.0 for 1-1.5 hours.

Images